A dispersion material obtained by dispersing fine particles of a crystalline polymer into a dispersion medium is utilized for paints, inks, cosmetics, lubricants, industrial oil, and the like, but a viscosity of the dispersion material may be sharply increased if an amount of the fine particles of the crystalline polymer would be increased, resulting in difficulty in using the dispersion material in some cases. Recently, attempts for producing a fuel by finely dispersing polyethylene or the like for the purpose of reusing waste plastics as energy have been made, however, an increase in the amount of fine particles of polyethylene or the like leads to an increase in viscosity of the dispersion material, causing the problem that the dispersion material may become hard to be handled and that, as a result, it is difficult to improve energy efficiency due to the difficulty in increasing the concentration of the dispersion material.
As a dispersant for a dispersion material of fine particles of polylactic acid has been proposed (see Patent Document 1). A dispersant usable for a dispersion material containing PTFE fine particles has also been proposed (see Patent Document 2).
For industrial oil to be used for a mobile device such as a damper and a clutch, it is necessary to adjust its viscosity, and the control of the viscosity of certain industrial oil has been realized by using an electroviscous fluid or a magnetoviscous fluid (see Patent Document 3, for example).
In recent years, there is an increasing demand for a rechargeable battery that is of a small size and light weight and has a high energy density as a driving power source of an electronic appliance such as a mobile phone, a personal computer, and a video camera. Among others, due to its high energy density at a high voltage, there has been widely used a rechargeable lithium ion battery that comprises a lithium-containing composite oxide used as a cathode active material; a carbonaceous material, a silicon compound, a tin compound, or the like capable of occluding or releasing lithium ions used as an anode material; a microporous film made from polyethylene, polypropylene, or the like as a separator disposed between the cathode and the anode electrode; and an aprotic organic solvent of a lithium salt such as LiBF4 and LiPF6 used as an electrolytic solution (see Patent Document 4, for example).